According to prior art it has hitherto not been possible to carry out force-free contour measuring on large-format and small-format flexible components, because the contour of the component changes as a result of the component's own weight and depending on its position in the space in which it is measured. Furthermore, stress that is introduced to the component for example by forming- and/or production processes can be covered up by an unfavourable spatial position of the component. Subsequently carried out alignment processes therefore may not lead to the results expected.
As a rule, welded skin fields, for example for fuselage cells, wings, horizontal tail units or the like, are distorted after the welding process as a result of the welding stress experienced so that the actual contour deviates from the desired contour. Nonetheless, the middle region of the skin field may still be in the region of the desired contour. The reason for this, among other things, is the skin field's own weight, as a result of which contour deviations can be covered up.
Automated alignment processes, which depending on the deviations between the desired contour and the actual contour deform the component in a controlled manner (e.g. by shot peening, bending processes, rolling processes or the like), would thus have no influence on the middle region of the skin field. In this case contour accuracy is achieved only by the influence of other regions of the skin field. However, if the position of the skin field in space changes, then the contour deviation that may under certain circumstances appear again due to the component's own weight may lead to installation difficulties, or to the component being rejected.